Abstract: A projecting device includes a light source configured to output an image light; a projection lens configured to externally project the image light; a camera configured to photograph an object positioned between the camera and an external projection surface of the image light that is projected; a light blocker configured to block the image light output by the light source during a blocking period; and at least one processor configured to: obtain illuminance information regarding illuminance of the external projection surface, set the blocking period during which the image light output by the light source is blocked, based on the illuminance information, set a photographing period within the blocking period, control the light blocker to block the image light output by the light source during the blocking period, and control the camera to photograph the object during the photographing period.

Abstract: A projector and display apparatus using a holographic optical element are provided. The projector includes a first display panel configured to emit a first beam of a first image, a second display panel configured to emit a second beam of a second image, a first transmissive holographic optical element configured to separate the first beam into a first diffracted beam and a second diffracted beam such that pixels of the first image overlap each other, a second transmissive holographic optical element configured to separate the second beam into a third diffracted beam and a fourth diffracted beam such that pixels of the second image overlap each other, a reflective holographic optical element configured to diffract and reflect the third and fourth diffracted beams in the same direction as the first and second diffracted beams such that the first image and the second image at least partially overlap each other, and a projection lens.

Abstract: A floating image display device includes: an image forming device configured to form a source image; a waveguide configured to output a light of the source image to another location by guiding the light; a holographic optical device provided on a proceeding path of the light output from the waveguide, the holographic optical device including a hologram pattern that diffracts incident light of a certain incident angle region output from the waveguide by a set target diffraction angle and a floating element including a plurality of corner reflectors and forming a floating image of the source image by forming an image of the light output from the holographic optical device at a certain location in mid-air.